I was astonished to hear the other day my wife come home from work (who is so far removed from any form of technology) tell me that her employers are looking at cloud technology, and then she started detailing bits about it. So I guess the understanding of cloud is starting to filter through to the masses.
There has been lots of noise about public cloud, private cloud and hybrid cloud. Gartner have recently made a pass at trying to define what a private cloud really is, so I thought I would share this with you (Thank You Thomas Bittman from Gartner.)
Gartner’s official definition of cloud computing is “A style of computing where scalable and elastic IT-enabled capabilities are delivered as a service to customers using Internet technologies.” Gartner also describe five defining attributes of cloud computing: service-based, scalable and elastic, shared, metered by use, uses Internet technologies. A key to cloud computing is an opaque boundary between the customer and the provider. Graphically, that looks like this:
When the customer does not see the implementation behind the boundary, and the provider doesn’t care who the customer is, you have a public cloud service. So what is private cloud?
Private cloud is “A form of cloud computing where service access is limited or the customer has some control/ownership of the service implementation.”
Graphically, that means that either the provider tunnels through that opaque boundary and limits service access (e.g., to a specific set of people, enterprise or enterprises), or the customer tunnels through that opaque boundary through ownership or control of the implementation (e.g., specifying implementation details, limiting hardware/software sharing). Note that control/ownership is not the same as setting service levels – these are specific to the implementation, and not even visible through the service.
The ultimate example would be enterprise IT, building a private cloud service used only by its enterprise. But there are many other examples, such as avirtual private cloud (the same as the example above, except replace ‘enterprise IT’ with ‘third-party provider’), and community clouds (the same as a virtual private cloud, except opened up to a specific and limited set of different enterprises).
Crystal Clear or Foggy?